1. Field of the Invention
The present invention generally relates to a shift control device that controls engagement of a clutch and controls a shift movement of a shift component using the power of a drive power source such as, for example, a motor. More particularly, the present invention relates to a straddle type vehicle comprising such a shift control device.
2. Description of the Related Art
In a shift control device, power from an electric motor rotates a shift shaft, and, with the rotation of the shift shaft, a clutch is disengaged and engaged and also shift gears are shifted (for example, see JP-A-Hei 11-82709 and U.S. Pat. No. 6,085,607B).
JP-A-Hei 11-82709 and U.S. Pat. No. 6,085,607B both propose that a shift shaft is rotated at a high speed before reaching a predetermined time and then the shift shaft is rotated at a low speed after the predetermined time to reduce a shift shock generated when the clutch is engaged.
Specifically, the shift control devices described in JP-A-Hei 11-82709 and U.S. Pat. No. 6,085,607B execute a pulse width modulation (PWM) control that changes a target angular position of the shift shaft at preset intervals and varies a duty ratio in accordance with the target angular position when the clutch that is once disengaged following a gearshift operation is engaged once again. By executing such a control, the shift shaft, as shown in FIG. 18 (noted as “shift spindle” in FIG. 18), rotates at a high speed in an angular range given during a period from a time t4 to a time t5 and existing in the proximity of an angular range in which the clutch is engaged and then rotates at a low speed in the angular range given after the time t5 and in which the clutch is engaged.